1 /* "Unimplemented" device 2 * 3 * This is a dummy device which accepts and logs all accesses. 4 * It's useful for stubbing out regions of an SoC or board 5 * map which correspond to devices that have not yet been 6 * implemented. This is often sufficient to placate initial 7 * guest device driver probing such that the system will 8 * come up. 9 * 10 * Copyright Linaro Limited, 2017 11 * Written by Peter Maydell 12 */ 13 14 #include "qemu/osdep.h" 15 #include "hw/sysbus.h" 16 #include "hw/misc/unimp.h" 17 #include "qemu/log.h" 18 #include "qemu/module.h" 19 #include "qapi/error.h" 20 21 static uint64_t unimp_read(void *opaque, hwaddr offset, unsigned size) 22 { 23 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque); 24 25 qemu_log_mask(LOG_UNIMP, "%s: unimplemented device read " 26 "(size %d, offset 0x%0*" HWADDR_PRIx ")\n", 27 s->name, size, s->offset_fmt_width, offset); 28 return 0; 29 } 30 31 static void unimp_write(void *opaque, hwaddr offset, 32 uint64_t value, unsigned size) 33 { 34 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque); 35 36 qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write " 37 "(size %d, offset 0x%0*" HWADDR_PRIx 38 ", value 0x%0*" PRIx64 ")\n", 39 s->name, size, s->offset_fmt_width, offset, size << 1, value); 40 } 41 42 static const MemoryRegionOps unimp_ops = { 43 .read = unimp_read, 44 .write = unimp_write, 45 .impl.min_access_size = 1, 46 .impl.max_access_size = 8, 47 .valid.min_access_size = 1, 48 .valid.max_access_size = 8, 49 .endianness = DEVICE_NATIVE_ENDIAN, 50 }; 51 52 static void unimp_realize(DeviceState *dev, Error **errp) 53 { 54 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(dev); 55 56 if (s->size == 0) { 57 error_setg(errp, "property 'size' not specified or zero"); 58 return; 59 } 60 61 if (s->name == NULL) { 62 error_setg(errp, "property 'name' not specified"); 63 return; 64 } 65 66 s->offset_fmt_width = DIV_ROUND_UP(64 - clz64(s->size - 1), 4); 67 68 memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s, 69 s->name, s->size); 70 sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem); 71 } 72 73 static Property unimp_properties[] = { 74 DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0), 75 DEFINE_PROP_STRING("name", UnimplementedDeviceState, name), 76 DEFINE_PROP_END_OF_LIST(), 77 }; 78 79 static void unimp_class_init(ObjectClass *klass, void *data) 80 { 81 DeviceClass *dc = DEVICE_CLASS(klass); 82 83 dc->realize = unimp_realize; 84 device_class_set_props(dc, unimp_properties); 85 } 86 87 static const TypeInfo unimp_info = { 88 .name = TYPE_UNIMPLEMENTED_DEVICE, 89 .parent = TYPE_SYS_BUS_DEVICE, 90 .instance_size = sizeof(UnimplementedDeviceState), 91 .class_init = unimp_class_init, 92 }; 93 94 static void unimp_register_types(void) 95 { 96 type_register_static(&unimp_info); 97 } 98 99 type_init(unimp_register_types) 100